Existing telephony services provide dedicated lines which permit certain types of signals to transfer from one location to another. Dedicated lines are designed to carry only certain types of signals i.e. video, data, voice or audio. Although the implementation of telephony systems in the U.S. varies greatly in terms of services and equipment available, telephony standard Digital Standard 3 (DS-3) provides a transmission capacity of 45 megabytes per second simultaneously in two directions and has sufficient bandwidth for carrying signals having multiple formats such as video, data, audio, and voice. However, DS-3 lines generally are dedicated lines for a particular type of format which means that in order to send video and audio signals, two different dedicated lines are used: a line for carrying video and a line for carrying audio. A line is dedicated for each type of signal format, because telecommunications systems are not capable of distinguishing between the different signal formats and routing them to the appropriate receiving device at the receiving end.
Dedicated telephone services are a disadvantage to today's businesses, because of the high costs and inconvenience of requiring wiring for each type of service. In addition, dedicated telephone services are expensive due to the telephone system's use of DS-3 lines for a single dedicated service. A business must pay for its use of the entire dedicated line even though only a small portion of the line's bandwidth may actually be used by the business.
In partial response to these disadvantages, a point-to-point wideband switching network for the transmission of voice, audio, video and data signals was developed. However, there are several limitations associated with this wideband switching network. Subscribers of the wideband switching network must call their local telephone exchange and their publicly switched digital network service provider to request routing of the information that they want to transmit. This is an inconvenience and requires preplanning. This system operates on fixed bandwidth at the DS-3 level, meaning that all transmissions occur at the DS-3 level and the user is charged for DS-3 bandwidth even if the bandwidth is not entirely used. In addition, this wideband switching network only provides NTSC style video service at the DS-3 level. There is still a need for multi-point service to multiple locations rather than from one specific location to one specific destination.